Crankcase gases from an internal combustion engine are ventilated from a crankcase of a relevant combustion engine. Crankcase gases may be dealt with in an environmentally friendly manner instead of being ventilated into the atmosphere. There are in some jurisdictions regulatory requirements that do not allow crankcase gases from certain types of combustion engines to be ventilated to the atmosphere.
Crankcase gases may comprise inter alia blow-by gases, oil, other liquid hydrocarbons, soot, and other solid combustion residues. In order to dispose of crankcase gases suitably, the gas is separated from oil, soot, and other residues. The separated gas may be led to an air intake of the combustion engine and the oil may be led back to an oil trough of the combustion engine, e.g. via an oil filter for removing soot and other solid residues from the oil.
U.S. Pat. No. 7,875,098 discloses a centrifugal separator for cleaning of crankcase gases. The centrifugal separator comprises a stationary casing defining an inner space, a spindle and a rotating member, which is attached to the spindle and arranged to rotate around an axis of rotation. The rotating member comprises a number of truncated conical separating discs which are provided in the inner space.
Separating discs, or separation discs, of a centrifugal separator are arranged in a disc stack with small interspaces between the separation discs. In the case of separation of crankcase gases, heavy constituents of the crankcase gases, such as oil and soot, are forced against inner surfaces of the separation discs and form droplets as they travel along the separation discs towards an outer periphery of the disc stack. The droplets are flung onto an inner wall of a housing of the centrifugal separator and are led out of the centrifugal separator via an oil outlet. The cleaned crankcase gases are led out of the centrifugal separator via a gas outlet.
The small interspaces between the separation discs in the disc stack of a centrifugal separator for crankcase gases may be blocked under certain circumstances, when a lot of soot and sticky particles is produced in a combustion engine e.g. due to high EGR (Exhaust Gas Recirculation) or due to a relevant combustion engine being worn. In particular, at the inner circumference of the separation discs, soot and/or other solid combustion residues may accumulate together with oil and/or other hydrocarbons. Entrance of the combustion gases into the interspaces between the separation discs in the disc stack thus, may be impeded. Accordingly, separation performance of the centrifugal separator may be reduced.